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    SubjectRe: [PATCH] x86, kdump, ioapic: Fix kdump race with migrating irq
    On Tue, Jan 31, 2012 at 02:08:29PM -0800, Eric W. Biederman wrote:
    > > The problem is that although kdump tries to shutdown minimal hardware,
    > > it still needs to disable the IO APIC. This requires spinlocks which
    > > may be held by another cpu. This other cpu is being held infinitely in
    > > an NMI context by kdump in order to serialize the crashing path. Instant
    > > deadlock.
    >
    > Can you test to see if kexec on panic still needs to disable the IO
    > APIC. Last I looked we were close if not all of the way there to not
    > needing to boot the kernel in pic mode?

    Ok, so you just blindly remove disable_IO_APIC from
    native_machine_crash_shutdown and re-run some panic tests on various
    machines? What about the disable_IO_APIC path in native_machine_shutdown?

    Also, where could I look to see if that work was done? Is that in the
    ioapic setup code?

    >
    > If we can skip the ioapic disable entirely we should be much more
    > robust.

    Agreed.

    Cheers,
    Don


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